1. Field of the Invention
The present invention relates to a device for preventing and detecting the falling of an object in a monitored area, and in particular on a railway line, and to a method for detecting the falling of an object on a railway line.
2. Background
In order to detect the falling of an object on a railway line, for example in a subway station, it is known to use a video camera placed above the railway lines. This solution is not, however, totally satisfactory because it requires significant and costly installation and servicing operations, and because it does not operate correctly if the viewing angle of the camera is masked.
Another known solution is to arrange a plurality of light-emitting diodes along the railway line, for example a diode every 25 cm. The diodes emit beams whose interruption can be detected. This solution entails a large number of diodes and detectors, which also involves significant and costly installation and servicing operations.
Another known solution for preventing the falling of objects or of people is to arrange over the entire length of the platform a system of landing doors, with alternating fixed physical barriers and moving doors in door opening areas designed to coincide with the doors of a train stopped at the platform, the opening of the doors of the train controlling the opening of the platform's landing doors. This solution presents the drawback of requiring a large quantity of equipment comprising motors and cables for opening the landing doors, also requiring significant and costly installation and servicing operations.